Exhaust-valve for steam-engines



7 (No Model.) 2 Sheets-Sheet 1.

G. B. RICHARDS.

EXHAUST VALVE FOR STEAM ENGINES.

No. 251,948. 1 Patented Jan; 3,1882.

X N m J j Z, L; i) P 11% V illll A (No Model.) 2 Sheets-Sh'eet 2,:

G. BRIGHARDS EXHAUST VALVE FOR STEAM ENGINES..

Patented Jan. 3 ,1882. B L Frau.

5 UNITED STATES PATENT OFFICE.

CHAR LESIB. RICHARDS, OF PHILADELPHIA, PENNSYLVANIA.

EXHAUST-VALVE FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 251,948, dated January 3, 1882.

Application filed November 7, 1881. (No model.)

To all whomitmay concern:

Be it known that I, CHARLES B. Bronanns, a citizen of the United States, residing in Philadelphia, Pennsylvania, have in vented certain My invention relates to the exhaustvalves ofthat classof high-pressure or condensing steam-engines in which these valves are arranged one at each end of the cylinder; and the objects of my invention are, first, to force the valve against its seat during that part of its movement in which pressure against the back of the valve is demanded for this purpose, and to relieve the valve or partially relieve it from this pressure during the other part of the movement; and, second, to prevent the waste of steam.

In the accompanying drawings, Figure 1, Sheet l,'is a vertical section of part of a steamcylinder, with the valve-chest and exhaustvalve, the latter being open; Fig. 2, a transverse vertical section on the line 1 2, Fig. 1; Fig. 3, Sheet 2, the same as Fig. l, with the. valve closed; Fig.4,a perspective view of the valve drawn to a reduced scale; Fig. 5, a perspective view of the pressure-frame and its I elastic diaphragm; Fig. 6, a perspective view difier from those under which a steam-valve .operates.

A represents in section a portion of the cylinder of a steam-engine, B part of the cylinder-head, and D the exhaust-chest, which G is the exhaust-port of the cylinder, d the valve-seat, and E the exhaust-valve, which is of the quadrangular form shown in Fig.4, and through which extends the opening an.

F is a pressure-frame, forming a secondary seat, a, for the valve, this seat corresponding substantially in shape and dimensions with the seat d for the face of the valve, and the opening}; in the pressureframe at its seat corresponding substantially with the port 0 at. the valve-seat cl. h

The above description will apply to valves heretofore used in connection with steam-engines, with this exception, that the opening p in the pressure-frame has been in the form of a recess, and has not extended through the frame, as in my improvement. The pressureframe, the character of which will be observed by reference to Fig. 5, extends from the back of the valve E into a chamber, f, made preterably in the bonnet H, an elastic diaphragm, P, which may be of sheet-copper, being clamped tothe bonnet and to the back of the pressure; frame in such a manner as to be perfectly steam-tight, the diaphragm crossing the space bctween'the frame and the margin of the said chamber f, which is sufficiently larger than the frame to permit the diaphragm to yield to the limited extent desired for permitting the frame to be forced with more or less pressure against the valve E, and to be moved away from the same. This diaphragm P cuts OK the communication between the chamber f and the exhaust-chest D when the valve is closed, as shown in Fig.3. 7

The dimensions of the back of the pressureframe are somewhat larger than those of the face of the valve-seat. A block, it, forming in the present instance part of the bonnet El, extends from the latter to within a short distance from the back of the valve E sufficient space mit the free escape of steam in the direction 'ion the block, Fig. 6, fit against the walls of the openingof the pressureframe and serve to steady the latter, while spaces .9 s between the said walls and the block afford free passages for the exhaust-steam to the chamber f. Spiral springs t it, contained in pockets formed in the bonnet, as shown in Fig. 7, exerta constant pressure against the frame and aid in maintaining its seat in contact with the back ofthe valve. When theexhaust-valvc is closed, as shown in Fig. 3, there is a commuhication between the interior of the cylinder and the chamberf, through 1 heexhaust-portO, through theopening in the valve,and through the abovementioned spaces 8 s, between the block h and the walls of the opening in the pressure-frame, so that the pressure of the steam in the cylinder must also be exerted onthe back of the pressure-frame and the back of the exposed portion of the diaphragm, and this steam, generally exceeding in pressure that within the exhaust chest, will exert against the back of the pressure-frame a moderate force, but sufficient to induce the frame to maintain the valve in steam-tight contact with its seat.

. When the valve is open, as shown in Fig.1,

V ate it.

the chamberf will be in communication with the interior of the exhaust-chest, as well as with theinterior of the cylinder, and hence the excess of pressure of steam against the back of the pressure-frame will cease, and consequently the valve will move more freely than before and will require less power to oper- The springs tare precautionary devices used for the purpose of keeping the valve against the seat whenever the pressure in the cylinder b:comes less than that in the exhaust-chest-a cJntingency which would be due to the excessive expansion of steam in the cylinder, and would cause the movement of the pressureframe from the valve and the valve from its seat. While this movement of the valve and frame would not cause a waste of steam it could not occur without disagreeable noises and a tendency to bruise the faces of the valve and its seats.

The block h may be dispensed with wheneverit is practicable to make the pressureframe shallow, as shown in Fig. 8.

It will be seen that myinvention is restricted in its application to exhaust-valves, and could not be adapted to ,steam-valves contained in a chest wherein the pressure of steam'is greater than in the cylinder, the several ports entering into the combination forming the subject of my invention being such that an excess'of pressure in the chest would result in the movin g of the pressure-frame away from the valve, and this would cause a wasteful leakage of steam.

I claim as my invention- 1. The combination of the exhaust-port G and exhaust-chest D of the cylinder of a steamengine with the reciprocating slide-valve E, the pressure-frame F, interposed between a chamber, f, and the interior of the chest, and passages whereby a communication is opened at one time between the said chamber and the interior of the cylinder, and at another time between the cylinder, chamber, .and exhaustchest, in obedience to the movement of the valve, all substantially as set forth.

2. The combination of the valve-chest D, valve E, and pressure-frame F with a block, it, extending into the opening ofthe said frame, substantially as specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

OHARLES B. RICHARDS.

Witnesses:

HARRY DRURY, HARRY SMITH. 

